Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4533_Библиотеки_им_академика_М_И_Перельмана
.pdf
beginning of conjoined
11 The Biological Basis ofCraniofacially Conjoined Twins
https://t.me/medicina_free
STAGES OF DEVELOPMENT
181
FERTILIZED EGG1 DAY
3 DAY
2 MONTH
6 MONTH
4 DAY BLASTOCYST
3 MONTH
7 MONTH
1,5 DAY2 DAY
1 MONTH
5 MONTH4 MONTH
8 MONTH
9 MONTH
Time frame of
twin formation
Fig. 11.6 The time frame of the development of conjoined twinning during pregnancy is well known. Source: Reprinted
from Macrovector/Shutterstock.com with permission
Gorlin [
27] created later (1990) a classica-
tion scheme with an emphasis on oral
duplication:
Fig. 11.7 Histology of normal blastocyst. Source: Reprinted
from Designua/Shutterstock.com with permission
III. Duplication of the maxilla with or without
mandible or pituitary duplication.
He further described pituitary duplication in
isolation but was uncertain regarding the existence of isolated mandibular duplication.
I. A single mouth with duplication of the max-
illary arch.
II. A supernumerary mouth laterally placed
with a rudimentary mandible.
III. A single mouth with replication of mandibu-
lar segments.
IV. Diprosopus with or without anencephaly.
In the rare case of the development of facial
duplication (diprosopus), different possible
mechanisms have been proposed [18, 20]. One
possible mechanism is the cranial bifurcation of
the notochord during neurulation (Fig.11.8). The
bifurcation causes two vertebral axes and neural
plates to develop alongside each other. Another
proposal is an increase in the expression of the
protein sonic hedgehog, which is essential for
craniofacial patterning during development [28].
The exact etiology of the condition is unknown.
Various mechanisms have been proposed, but the
182
Histological site of the
D
ARCHENTER
LATE GASTRULA POUCH FORMATION SOMITE FORMATION NEURULATION
https://t.me/medicina_free
U. Meyer
most accepted one is due to the abnormality of
sonic hedgehog genes and protein (Shh). Shh
protein and corresponding genes are responsible
for signaling and patterning of craniofacial structure. It also organizes the embryonic cells to specic areas, which later develops into specialized
organs. In the brain, absence of Shh protein leads
to holoprosencephaly and failure to move optic
disc leads to cyclopia. If the activity of protein is
increased, it leads to duplication of organs leading to diprosopus. Few authors also feel that the
anomaly is due to the fusion of the parallel notochord in close proximation or ssion of single
notochord because of the abnormality of Dix
DEVELOPING
MESODERM
NEURAL
PLATE
FUTURE
NOTOCHORD
DEVELOING
NOTOCHORD
homeobox gene. But till date, no genetic abnormality has been recorded with diprosopus.
11.8 Early Diagnostics
ofConjoined Twins
Prenatal diagnosis using ultrasonography, computed tomography (CT) scan, and magnetic
resonance imaging (MRI) is possible. Most conjoined twins are detected in the pre-natal period
by ultrasound [29]. Ultrasound has revolutionized the management of multiple pregnancies
and their complications (Fig. 11.9). Increasing
beginning of facial
duplication development
COELOM
NEURAL TUBE
NOTOCHOR
MESODERMAL
SEGMENT
COELOM
ON EPIDERMIS
ARCHENTERON
Fig. 11.8 Histology of facial development. Disturbance
of the normal notochord formation during neurulation
through cranial bifurcation is a proposed mechanism of
Fig. 11.9 Ultrasound investigations are the primary
mode of twin pregnancy analysis. Modern 3D ultrasound
machines enable a precise documentation of facial struc-
ARCHENTERON
GUT
facial duplication. Source: Reprinted from Betty Ray/
Shutterstock.com with permission
tures. Source: Reprinted from Semmick Photo/
Shutterstock.com with permission
11 The Biological Basis ofCraniofacially Conjoined Twins
https://t.me/medicina_free
183
frequency of twin pregnancies mandates therefore familiarity of all clinicians with the relevant
pathologies and evidence-based surveillance
and management protocols for their care. Such
twins can often at this stage be classied according to the most prominent site of connection:
the thorax (thoracopagus), abdomen (omphalopagus), sacrum (pygopagus), pelvis (ischiopagus), skull (craniopagus), face (cephalopagus),
or back (rachipagus). The rst trimester (11–
13w+6days) ultrasound is the best method for
diagnosing conjoined twins early in pregnancy.
Given the high risk of preterm delivery in twins,
accurate rst trimester dating is important in
later management of the pregnancy. After dating
and determination of the diagnosis of multiple
pregnancy, the most important additional information to determine is the precise number of
fetuses and the chorionicity (number of placentae) and amnionicity (number of amniotic sacs)
of the pregnancy. While the majority (>80%) of
twin pregnancies are dichorionic, monochorionic
pregnancies are associated with worse perinatal
outcomes, are affected by several conditions specic to twins sharing a placental circulation, and
require signicantly more antenatal surveillance.
As the rarest complication of monochorionic
pregnancy is conjoined twinning, a condition
resulting from very late splitting of the blastocyst and occurring in only 1% of monochorionic
twin pregnancies, careful ultrasound diagnosis
with high resolution devices is of special relevance [29–33]. The diagnosis remains often
easy, even if some of the congenital abnormalities cannot be seen at these gestational stages.
Increased nuchal translucency is common, even
in fetuses with two independent hearts and no
cardiac congenital abnormalities in the embryopathological study. The early diagnosis of this
condition is mandatory to allow an early information of parents. Advances in ultrasound mean
in consequence that conjoined twins are most
commonly identied in the rst trimester when
many parents will opt for termination of pregnancy in view of the high risk of morbidity and
mortality in an ongoing pregnancy. In families
choosing to continue pregnancies, around 25%
would be expected to survive to discharge and
almost all with signicant morbidity. The prognosis is ultimately determined by the degree
and site of the junction between the twins, and
therefore detailed ultrasound studies are necessary to fully explore the nature of the connections between the twin pair. The most common
site of union is at the thorax with the twins facing each other, and bowels, liver, and hearts may
be shared. Mapping blood vessels and structures
can help plan postnatal surgery.
For more detail, an MRI investigation is useful even in the prenatal period. In the postnatal
period it is important to get insight into the anatomical extent of twinning. Additionally, when
separation is planned, planning of the surgical
strategy is aided by accurate preoperative imaging. The area of fusion largely determines the
imaging modalities used. Thoracic conjunction
is most common and requires cardiac assessment. Magnetic resonance imaging and computed tomography provide excellent anatomic
and bone detail, demonstrating organ position,
shared structures, and limited vascular anatomy
in the craniofacial region. Contrast material
radiography allows evaluation of the gastrointestinal and urogenital tracts, and a shared liver
requires assessment of anatomy, vascularization, and biliary drainage. Angiography helps
dene specic vascular supply, which is useful
in determining the distribution of shared structures between the twins at surgery. Each set of
conjoined twins is unique. An imaging strategy
to accurately dene anatomic fusion, vascular
anomalies, and other associated abnormalities
is important for prognostic information and surgical planning.
However, new cases should be critically evaluated not only with radiological imaging but
also by genetic diagnostics [34]. Surgery to separate conjoined twins may range from very easy
to very difcult depending on the point of
attachment and the internal parts that are shared.
Most cases of separation are extremely risky
and life threatening. In many cases, the surgery
184
https://t.me/medicina_free
U. Meyer
results in the death of one or both of the twins,
particularly if they are joined at the head or
share a vital organ.
References
1. Pachajoa H, Hernandez-Amaris MF, Porras-Hurtado
GL, Rodriguez CA.Siamese twins with craniofacial
duplication and bilateral cleft lip/palate in a ceramic
representation of the Chimú culture (Peru): a comparative analysis with a current case. Twin Res Hum
Genet. 2014;17:211–4.
2. Kaufman MH. The embryology of conjoined twins.
Childs Nerv Syst. 2004;20:508–25.
3. Spencer R. Conjoined twins: developmental malformations and clinical implications. Baltimore and
London: JHU Press; 2003.
4. Mutchinick OM, Luna-Muñoz L, Amar E, Bakker
MK, Clementi M, Cocchi G, da Graça DM, Feldkamp
ML, Landau D, Leoncini E, Li Z, Lowry B, Marengo
LK, Martínez-Frías ML, Mastroiacovo P, Métneki
J, Morgan M, Pierini A, Rissman A, Ritvanen A,
Scarano G, Siffel C, Szabova E, Arteaga-Vázquez
J.Conjoined twins: a worldwide collaborative epidemiological study of the international clearinghouse
for birth defects surveillance and research. Am J Med
Genet C Semin Med Genet. 2011;157C:274–87.
5. Boer LL, Schepens-Franke AN, Oostra RJ. Two
is a crowd: two is a crowd: on the enigmatic etiopathogenesis of conjoined twinning. Clin Anat.
2019;32(5):722–41.
6. Ahmadi F, Keramat N, Haghighi H.Conjoined twin.
Int J Fertil Steril. 2012;6:135–6.
7. Casale P, Grady RW, Waldhausen JH, Joyner BD,
Wright J, Mitchell ME. Cloacal exstrophy variants.
Can blighted conjoined twinning play a role? J Urol.
2004;172:1103–6. discussion 1106–1107
8. Millar AJW, Rode H, Thomas J, Hewitson
J. Thoracopagus conjoined twins. In: Parikh DH,
DCG C, Auldist AW, Rothenberg SS, editors. Pediatric
Thoracic Surgery. London: Springer; 2009.
9. Berrin K, Larco M. The Spirit of Ancient Peru:
Treasures from the Museo Arqueológico Rafael Larco
Herrera. NewYork: Thames and Hudson; 1997.
10. Caneld D, Brignolo L, Peterson PE, Hendrickx
AG. Conjoined twins in a rhesus monkey (Macaca
mulatta). J Med Primatol. 2000;29:427–30.
11. Beckwith JB. Congenital malformations: from
superstition to understanding. Virchows Arch.
2002;461:609–19.
12. Opitz JM, Herrmann J, Pettersen JC, Bersu ET,
Colacino SC. Terminological, diagnostic, nosological, and anatomical-developmental aspects of
developmental defects in man. Adv Hum Genet.
1979;9:71–164.
13. Spranger J, Benirschke K, Hall JG, Lenz W, Lowry
RB, Opitz JM, Pinsky L, Schwarzacher HG, Smith
DW. Errors of morphogenesis: concepts and terms.
Recommendations of an international working group.
J Pediatr. 1982;100:160–5.
14. DeSesso JM. The arrogance of teratology: a brief
chronology of attitudes throughout history. Birth
Defects Res. 2019;111:123–41.
15. Sharma G, Mobin SS, Lypka M, Urata
M.Heteropagus (parasitic) twins: a review. J Pediatr
Surg. 2010;45:2454–63.
16. Oostra RJ, Baljet B, Verbeeten BW, Hennekam
RC. Congenital anomalies in the teratological collection of museum Vrolik in Amsterdam, The
Netherlands. V: Conjoined and acardiac twins. Am J
Med Genet. 1998;80:74–89.
17. Yahaya RS, Suwaid MA, Hassan S, Lawal Y, Hassan
I, Gwaram BA, etal. “Three-eyed” infant: a case of
partial facial duplication (Diprosopus monocephalous
triophthalmos) west Afr. J Radiol. 2018;25:79–83.
18. Suryawanshi P, Deshpande M, Verma N, Mahendrakar
V, Mahendrakar S. Craniofacial duplication: a case
report. J Clin Diagn Res. 2013;7:2025–6.
19. Hähnel S, Schramm P, Hassfeld S, Steiner HH, Seitz
A. Craniofacial duplication (diprosopus): CT, MR
imaging, and MR angiography ndings case report.
Radiology. 2003;226:210–3.
20. Hemachandran M, Radotra BD. Partial duplication
of head—a rare congenital anomaly. Indian J Pathol
Microbiol. 2004;47:537–9.
21. Weber MA, Sebire NJ.Genetics and developmental
pathology of twinning. Semin Fetal Neonatal Med.
2010;15:313–8.
22. Guttmacher AF, Nichols BL.Teratology of conjoined
twins. Birth Defects Orig Art Ser. 1967;3:3–9.
23. Kapur RP, Jack RM, Siebert JR.Diamniotic placentation associated with omphalopagus conjoined twins:
implications for a contemporary model of conjoined
twinning. Am J Med Genet. 1994;52:188–95.
24. Bidondo MP, Groisman B, Tardivo A, Tomasoni
F, Tejeiro V, Camacho I, Vilas M, Liascovich R,
Barbero P.Diprosopus: systematic review and report
of two cases. Birth Defects Res A Clin Mol Teratol.
2016;106:993–1007.
25. Martyn I, Kanno TY, Ruzo A, Siggia ED, Brivanlou
AH. Self-organization of a human organizer by
combined Wnt and nodal signalling. Nature.
2018;558:132–5.
26. Barr M Jr. Facial duplication: case, review, and
embryogenesis. Teratology. 1982;25:153–9.
27. Gorlin RJ. Craniotubular bone disorders. Pediatr
Radiol. 1994;24(6):392–406.
28. Murdoch JN, Copp AJ. The relationship between
sonic hedgehog signaling, cilia, and neural tube
defects. Birth Defects Res A Clin Mol Teratol.
2010;88:633–52.
29. Townsend R, Khalil A.Ultrasound surveillance in twin
pregnancy: an update for practitioners. Ultrasound.
2018;26(4):193–205.
30. Alkhateeb M, Mashaqbeh M, Magableh S, etal. Early
prenatal diagnosis of thoracopagus twins by ultrasound. Acta Inform Med. 2015;23:60–2.
11 The Biological Basis ofCraniofacially Conjoined Twins
https://t.me/medicina_free
185
31. Cuillier F, Dillon KC, Grochal F, et al. Conjoined
twins: what ultrasound may add to management. J
Prenat Med. 2012;6:4–6.
32. Chen C-P, Hsu C-Y, Su J-W, et al. Conjoined twins
detected in the rst trimester: a review. Taiwan J
Obstet Gynecol. 2011;50:424–31.
33. Spitz L. Conjoined twins. Prenat Diagn.
2005;25:814–9.
34. Kompanje EJ. Very rare congenital malformations:
responsibilities of scientists. The case of rachipagus
conjoined twins. Fetal Diagn Ther. 2006;21:319–20.
Biological Basis ofCraniofacial
https://t.me/medicina_free
Soft Tissue Malformations
KaiWermker
12
12.1 Introduction
Soft tissue malformations in the head and neck
region are a heterogeneous group of pathologic
ndings involving different tissues like skin, vessels and muscles. The malformations can involve
only one dened part of craniofacial tissue, e.g.
congenital nevi which only involves the skin, or
they can affect multiple tissues, e.g. vascular malformations like haemangioma that can be found in
supercial soft tissues (like the skin) and deeper
tissues like muscle, fascia or even bone. The malformations are mainly hereditary, but some are
also discussed developing spontaneously. This
chapter focuses on the aetiology and epidemiology
of these malformations and their biological basis,
including some aspects concerning diagnostics.
A rough classication can be made by differentiating the so-called phakomatoses, nevoid
skin malformations and vascular malformations
not related to phakomatoses.
12.2 Phakomatoses
Several neuro-oculo-cutaneous syndromes are
grouped together as so-called phakomatoses,
affecting in various degrees the craniofacial soft
K. Wermker (*)
Department of Oral and Cranio-Maxillofacial
Surgery, Plastic and Aesthetic Operations, Klinikum
Osnabrueck, Osnabrueck, Germany
e-mail: kai.wermker@klinikum-os.de
tissues and sometimes also the hard tissues. The
neurocutaneous disorders are linked to structures
derived from the embryogenic ectoderm, whereas
to various amounts also mesodermal and endodermal tissues also may be involved. Often the
central nervous system, the skin and the eyes are
involved, classifying them as multisystem disorders. Genetic and acquired phakomatoses can
occur in the craniofacial area, and the clinical
extent and severity vary considerably.
Due to the involvement of multiple organs and
systems, diagnosis in patients has to consider
various disciplines and aspects. In a multidisciplinary approach, clinical examination should be
performed in the elds of paediatrics, neurology,
ophthalmology, dermatology, dentistry and oral
and maxillofacial surgery, and internal medicine.
Complete imaging of the cranium, head and neck
region, thorax and abdomen should be performed
using MRI (magnetic resonance imaging) and/or
CT (computed tomography) scans. If a phakomatosis is suspected or even conrmed, the patient
and his family should be referred to human
geneticist.
The following syndromes and disorders with
affection and involvement of soft tissues of the
head and neck are attributed to this group: the
nevoid basal cell carcinoma syndrome (NBCCS,
Gorlin-Goltz syndrome), neurobromatosis (types
I (NF1, Recklinghausen disease) and II), SturgeWeber syndrome, von Hippel-Lindau disease,
ataxia telangiectasia, incontinentia
pigmenti,
© Springer Nature Switzerland AG 2021
U. Meyer (ed.), Fundamentals of Craniofacial Malformations,
https://doi.org/10.1007/978-3-030-46024-2_12
187
188
ab
https://t.me/medicina_free
K. Wermker
tuberous sclerosis and Wyburn-Mason syndrome.
In the following, disorders with relevant pathology
in the craniofacial region are described in more
detail.
12.2.1 Nevoid Basal Cell Carcinoma
Syndrome (NBCCS, GorlinGoltz Syndrome)
The nevoid basal cell carcinoma syndrome
(NBCCS) was rst described in 1960 by Gorlin
and Goltz and is therefore synonymously known
as Gorlin-Goltz syndrome. Its prevalence is 1in
56,000 to 164,000 with higher frequency in
Australia. NBCCS is inherited in an autosomal
dominant fashion (70–80% of all NBCCS cases),
but 20–30% of new Gorlin-Goltz patients are
caused by spontaneous de novo mutations.
Underlying genetic mechanisms are mutations in
the PTCH1 (patched) gene on chromosome 9q.
PTCH1 as tumour suppressor gene encodes for a
transmembrane receptor protein of the sonic
hedgehog family. This protein is involved in cell
regulation and cell growth, and its (homozygous)
inactivation increases the risk of tumorigenesis.
The highest risk of tumour development is given
for cutaneous malignancies, especially basal cell
carcinoma (BCC)—leading to the name of this
syndrome. According to the “two-hit” theory for
tumour suppressor genes, NBCCS patients with
one (inherited) defect in the PTCH1 gene have
the disorder, and a second mutation (e.g. caused
by ultraviolet light (UV) through sun exposure or
ionizing radiation like X-rays) leads to full
expressivity and development of a neoplasm.
Depending on the affected tissue, different
tumour entities are possible [1–4].
Leading clinical and radiographic symptoms
and signs of NBCCS are multiple non-melanoma
skin cancers (NMSC, especially basal cell carcinoma (BCC; see Fig.12.1), details below), palmar and plantar pits, a distinct facial appearance
(characterized by macrocephaly with frontal and
temporal edge conguration, broadened root of
the nose and hypertelorism, and prognathism of
the mandible with the appearance of progenia
and dental Angle class III), development of often
multiple odontogenic keratocysts (formerly also
known as keratocystic odontogenic tumour; see
Fig.12.2) in the lower and upper jaw in three of
four NBCCS patients, intracranial pathologies
like early calcication of the falx cerebri, bridging of the sella turcica and in up to 10% formation of medulloblastoma, skeletal disgurements
like bid ribs and scoliosis and occurrence of
other tumours (bilateral ovarian bromas, cardiac
bromas) [5–8].
Table 12.1 gives an overview of major and
minor criteria of NBCCS.NBCCS is conrmed
if a patient shows two major criteria or one major
and two minor criteria [9].
Skin tumours in NBCCS are by far most often
BCCs. The number and extent of BCC increase
Fig. 12.1 (a, b) Different types of facial basal cell carci-
noma (BCC). Nodular type of basal cell carcinoma
(BCC), localization at the lower eyelid (a) and scleroder-
miform type of BCC (b), localized at the lateral forehead
and temporal
ab
12 Biological Basis ofCraniofacial Soft Tissue Malformations
https://t.me/medicina_free
189
Fig. 12.2 (a, b) Keratocystic odontogenic tumours
(KOT, keratocysts). X-ray (orthopantomogram) of a
26-year-old woman with three keratocystic lesions of the
Table 12.1 Diagnostic criteria in nevoid basal cell carci-
noma syndrome (NBCCS, Gorlin-Goltz syndrome)
Region/
organ Major criteria Minor criteria
Skin More than 2
Craniofacial/
jaws
Intracranial Ectopic
Skeleton Rib deformity
Other
tumours
Genetics Family history
NBCCS nevoid basal cell carcinoma syndrome, BCC
basal cell carcinoma, CLP cleft lip, alveolus and palate
BCCs or 1 BCC
in patients
<20years; 3 or
more palmar or
plantar pits
Odontogenic
keratocysts
calcication or
calcication of
the falx cerebri
in patients
<20years
(bid, fused or
splayed)
(rst-degree
relative with
NBCCS)
Macrocephaly;
congenital
malformations like
CLAP, frontal
bossing, eye anomaly
(cataract, coloboma,
etc.); hypertelorism
Bridging of the Sella
turcica
Other skeletal
deformities: Sprengel
deformity, pectus
excavatum, poly- or
syndactyly; vertebral
anomalies
Ovarian broma,
cardiac broma
typically with age, but even younger patients can
show BCC.BCC risk is increased in areas with
high UV exposure like the face, but in Gorlin-
jaw (a, white arrows): one major keratocyst of the upper
right jaw and two minor lesions in the anterior mandible.
(b) Histologic aspects of KOT/keratocysts (HE, 100x)
Goltz syndrome patients NMSC also can occur in
regions with very low sun exposure (e.g. palmar
and plantar). BCC is a local aggressive form of
skin cancer, leading to destruction of local tissues
if not treated properly, but usually metastasization does not occur. The more aggressive entities
of NMSC also found in NBCCS patients sometimes are metatypical BCC and basosquamous
carcinoma (BSC), both of which are able to disseminate and the latter one showing histologic
and biologic characteristics of cSCC (Fig.12.3).
12.2.2 Neurobromatosis (NF)
Three types of disorders, which are characterized
by the development of benign tumours in the nervous system, are denominated as neurobromatosis types 1 and 2 and schwannomatosis [10–12].
Neurobromatosis type 1 (NF-1, syn.:
Recklinghausen disease) is the most common NF
type with a prevalence of approximately 1–3500in
Western countries. NF1 is characterized by the
development of nerve sheath tumours—neurobromas—along the nerves and in the skin in all
parts of the body. It is caused by microdeletion
and mutations in the NF-1 gene on chromosome
17q11.2, encoding for neurobromin which is
part of the RAS oncogene pathway. Through disturbance of cell signalling, tumour development is
enhanced especially in nervous tissue. Inheritance
is autosomal dominant, but up to 50% of all NF-1
cases can be attributed to spontaneous mutations.
NF-1 is a progressive disease with rst signs and
symptoms starting in early childhood and aggra-
190
ab
https://t.me/medicina_free
K. Wermker
c
Fig. 12.3 (a, b, c) Histologic characteristics of basosqua-
mous carcinoma (BSC). In conventional histology (a, HE
400×), BSC shows nuclear pleomorphism, with many
mitotic cells showing atypical mitosis, and a loss of palisades, which are usually typical for BCC (basal cell carcinoma). Immunohistochemical staining with BerEP4 (b,
vates in later age and adolescence. Nevertheless,
if no complications (e.g. severe nerve compression symptoms) or malignant tumours (e.g. switch
from benign neurobroma to malignant nerve
sheath tumour/malignant schwannoma) occur,
life expectancy is normal. A chief complaint of
NF-1 patients is disgurement (see clinical signs
and symptoms below). Due to a penetrance that
varies tremendously (from only few mild symptoms without any impact on normal life up to
severe rapidly progressive course), prognosis is
difcult and depends on the individual situation
[13, 14].
Pathognomonic symptoms are so-called “café
au lait” macules that can be found even in newborn and grow during life—often increasing in
BerEP4 100x) illustrates irregular mixture of BCC typical
areas (red) and dedifferentiated areas with more similarities to squamous cell carcinoma (SCC). Conventional histology of the same tumour (c, HE 100x) depicts the
aforementioned BSC characteristics
size and number during hormonal changes
(puberty, gravidity). The lesions are at and of
brown colour with smooth or irregular borders.
Furthermore, benign neurobroma of the skin is
typical. These nodules vary in size and number
and can grow up to large tumours (progredient
with time), leading to disgurement and functional problems or even damage of the adjacent
tissue and organs. The neurobromas can be subdivided into plexiform types (which encase or
inltrate the nerves and blood vessel and reach
into deeper tissues), solitary neurobromas
(located at deep nerve trunks) and schwannomas
(benign nerve sheath tumour). The latter can turn
into malignant tumours with a lifetime risk of
8–12%. The neurobromas can occur at every
ab
12 Biological Basis ofCraniofacial Soft Tissue Malformations
https://t.me/medicina_free
191
site and of course also in the craniofacial region
(in the skin and also intraorally in the mucosa),
and deeper tissues can be involved [15, 16].
Figure 12.4 shows a patient with NF-1, who
developed multiple extended neurobromas of
the upper jaw, left midface and orbit—requiring
partial maxillectomy and midfacial tumour resection including exenteration of the orbit—rehabilitated with a facial prosthesis. Another skin
anomaly is axillar or inguinal freckling. In the
ophthalmologic eld, the so-called Lisch nodules
(accumulation of dendritic melanocytes in the
iris) and gliomas at the optic nerve or chiasma
opticum can occur. Bony symptoms can involve
the extremities (bowing and increased fracture
risk with compromised bone healing and
increased risk for pseudarthrosis, unilateral
accelerated growth), scoliosis and also craniofa-
cial bones (sphenoid dysplasia, defects in the
area of the maboid suture). Furthermore, in some
NF-1 patients noticeable problems in the neurobehavioural and musculoskeletal eld were
described: motor decits, attention-decit/hyperactivity disorder, autism, epilepsy and muscle
weakness [17].
NF-1 is secured with the following clinical
diagnostic criteria: at least six café au lait macules, at least two neurobromas or at least two
Lisch nodules [18].
Neurobromatosis type 2 (NF-2) is characterized by the development of acoustic neuromas
(vestibular schwannoma, VS), which are benign
tumours of the nerve sheath of the eighth cranial
nerve (N. vestibularis). In a relevant proportion
of NF-2 patients, this kind of intracerebral tumour
occurs bilaterally, and furthermore, also other
Fig. 12.4 (a, b) Patient with neurobromatosis type 1
(NF-1, Recklinghausen disease). Adult patient who suffered from multiple neurobromas of the left face and
orbit, leading to multiple resective and reconstructive
operations including exenteration of the left orbit due to
compression syndromes and growth intracranially. (a)
Remarkable is the asymmetry also in the midface due to
subcutaneous and deeper neurobroma growth.
Rehabilitation was achieved by multiple steps of reconstructive ap surgery and insertion of craniofacial orbital
implants to retain the facial prosthesis (b)
Соседние файлы в папке Библиотека им академика М.И. Перельмана